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RE: using spawn functions to avoid fork() errors
- From: "Steven Bardwell" <SBardwell at lbmsys dot com>
- To: <cygwin at cygwin dot com>
- Date: Thu, 6 Feb 2014 17:14:28 -0500
- Subject: RE: using spawn functions to avoid fork() errors
- Authentication-results: sourceware.org; auth=none
- References: <000001cf226a$e8d47830$ba7d6890$ at lbmsys dot com> <52F2606E dot 4030204 at cygwin dot com> <012a01cf2342$6d7dd310$48797930$ at lbmsys dot com> <52F3E1C4 dot 4020801 at cygwin dot com>
- Reply-to: <sbardwell at lbmsys dot com>
> On 2/6/2014 8:50 AM, Steven Bardwell wrote:
> > Larry - thanks for the link to the source for the spawn() APIs. It
works
> > perfectly on my 32-bit install (where, as it happens, the fork() issue
> > never shows up either).
> >
> > However, on my 64-bit install, the spawnv() call is returning with an
> > error -- 'No such file or directory' -- when I try to spawn /bin/sh.
> > I have attached the output from 'strace' on this process. If you look at
> > line 602, I think you can see where the exception gets generated. Can
> > you see what is going on? I tried to create a simple test program that
> > shows the problem, but (so far) they all work. Thanks.
>
> Interesting. No, off hand, the strace output doesn't shed any light on
> the situation for me either. Clearly an access violation occurs when
> /bin/sh is spawned but if it only happens in your specific code and not
> in a simple invocation of spawn(), that suggests a possible usage problem.
> I know, that's not much help. ;-)
>
> --
> Larry
>
I am still trying to create a simple example, but the fact that it works on
the 32-bit
install inspired me to look again at the strace output, comparing the output
from
the install that works with the 64-bit strace output that shows the problem.
Can you look at this section? /bin/sh (the program that is getting
spawned)
gets loaded and starts running with PID 1464, but /bin/sh is failing :
47 8674492 [main] ulpd 2116 child_info::sync: n 2, waiting for
subproc_ready(0x258) and child process(0x26C)
4 4 [main] sh (1464)
**********************************************
296 300 [main] sh (1464) Program name: C:\cygwin64\bin\sh.exe (windows
pid 1464)
52 352 [main] sh (1464) OS version: Windows NT-6.1
34 386 [main] sh (1464)
**********************************************
233 619 [main] sh (1464) sigprocmask: 0 = sigprocmask (0, 0x1802BBC68,
0x0)
287 906 [main] sh 1464 child_copy: cygheap - hp 0x254 low 0x1802DA410,
high 0x1802E46D0, res 1
122 1028 [main] sh 1464 child_copy: done --- Process 1464, exception
c0000005 at 00000001800448D0
My process (PID=2116) creates the new process (/bin/sh with PID=1464), but
then /bin/sh craps out.
Does that shed any light on what might be the issue?
Steve
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